First, you need to clear the zone of the trash mobs. The dark nimbus mobs cast an AE DoT that is curable(Arcane), but try to stay away from them if you can.
On the entrance floor in the first room on the right at ( -6, 0, 27 ) /waypoint -6, 0, 27, examine The Skeletal Remains of a Fallen Soldier on the floor to get the quest The Warning Remains.
There are 4 Knight statues (Sir Xavier ( 23, -15, 94 ) /waypoint 22.89, -14.92, 94.02, Sir Anders ( 151, -21, 173 ) /waypoint 151.08, -21.33, 173.05, Sir Erondas ( 179, -19, 261 ) /waypoint 179.27, -19.13, 260.53, Sir Mastri ( -70, -15, 145 ) /waypoint -69.90, -14.64, 144.75) in the zone, 1 near each dreadfiend. You must move each statue into the correct alcove in the Chapel of Penance ( 216, -21, 78 ) /waypoint 216.11, -21.33, 78.06 (the book at nearby lists Sir Anders from West Freeport, Sir Xavier from North Freeport, Sir Mastri from East Freeport and Sir Erondas from South Freeport). You will see an emote when you've done it correctly.
Ghosts of each Knight will spawn and move to the Temporal Chamber area ( 216, -17, 138 ) /waypoint 216.04, -17.39, 138.10. The ghosts will be joined by the ghost of Gynok Moltar. Once all 4 ghosts are there, the center Sand Timer will become clickable; flip it over to set back time and begin the ring event. Once you activate the timer, speak to each Ghost to activate them.
This will spawn mobs throughout the zone from destroyable gargoyle statues, a glooming acrolith (destroy these otherwise you will get respawns - this also seems to kill all mobs that came from the statue)
Nameds will spawn in the original locations of the Knight statues:
Sir Loros Highgarden - puts a lot of uncurable Arcane (divine dmg) on all players in range: run into Sir Xavier's ghost to get cured (you can't stand next to him - run in then away). He dismounts when his health gets down to about 30%, at which point his horse joins the fight. His horse dies when he does, so there's no point changing targets.
He seems to be bugged. Every time we tried to kill him he would stop and become non-aggro. We had to zone out to fix it. Apparently if you do too much damage he becomes unattackable. If you can, just auto-attack him to death, and have your healer keep everyone alive. Don't know how much dmg is too much, because when we finally got it to work all 5 of us were just auto-attacking.
While we could not kill slow enough to put down Sir Loros Highgarden as previously suggested, we discovered that if you can kill him within 8-10 seconds he will go down, and not reset to an unkillable state. It takes about 1.9 Million damage to put him down in a Level 90 instance. So bring your big hitters and time warp.
We seemed to have better luck when everyone was standing on top of the mob. He breaks if you are out of range of the Arcane.
Tsiet'Sozlt same as above - but he puts more uncurable effects on you (Elemental, Arcane, Trauma), run into Sir Anders for cure.
Gromkey same as above - but also spawns a pet as well - run into Sir Erondas for cure.
Arch-bishop Joltan same as above - but also puts curse on all, and will spawn a duplicate of one group member (that member will be stunned while the mob double is alive) - run into Sir Mastri for cure. (There always seems to be some mob that keeps you from getting to the last mob solo and this is the one for this zone. You literally kick your own butt.)
A chest will spawn in the Chapel of Penance - key drops from hailing and killing a phantasmal drunkard in the Great Hall ( 140, -23, 88 ) /waypoint 139.83, -22.71, 88.22
Chest was in a room near the entrance for us, and did not contain a key, but had 5pp 5g.
Found Drunkard's Footlocker here - ( 12, 0, 24 ) /waypoint 12, 0, 24
After all four nameds are down the room near the beginning of zone with the spider webs covering it will be open.
Go back to the Temporal Chamber and hail Gynok Moltor. This will open up the passage that was blocked by cobwebs. Proceed to the room Broken Stair ( -16, -14, 224 ) /waypoint -16.43, -14.46, 224.49. The Ghost of Gynok Moltor, Sir Xavier, Sir Anders, Sir Erondas, Sir Mastri will be standing at the top of the room. Hail Gynok and Sir Xavier, Sir Anders, Sir Erondas, Sir Mastri will run to the 4 corners of the room.
Then Gynok will run down the stairs and kneel down and The Eidolon of Depravity will spawn just in front of him. If you are far enough away he will not engage until you pull.
When you see the message: "You've turned against him, you've all betrayed him, die!", he is immune to all damage. To make The Eidolon of Depravity vulnerable to damage again, pull it to either Sir Xavier, Sir Anders, Sir Erondas or Sir Mastri. (Unless you are very quick, this will end up killing the ghost you pulled him to).
You must do enough damage before he becomes immune and you have him kill one of Sir Xavier, Sir Anders, Sir Erondas, Sir Mastri. Once they are all down you have about 45 seconds. If The Eidolon of Depravity is not killed by then he will run over to Gynok once he gets to him he will despawn and respawn as Gynok Moltor, an Epic x4 mob(!)
For those of you doing the quest, A Knight's Word, the lost testament is on the lower floor of this room. Additionally, at the top if this room is a banner that may be harvested and put in your room; the azure tapestry of the forsaken. If the entire party clicks on it together, you can all get one!